@Fil Albuquerque,
Furthermore if one is willingly admitting several degrees of complexity in the structuring of a set of systems including moral systems, the usage of an Absolute or "Universality" as adequate terming, even considering an open infinite set, would just require the biggest possible set at a given time frame, which must exist if any order of grandeur exists, you don't even have to describe it, or particularize its characteristics...
Moral relative models are not only susceptible to more advanced moral relative models, but they must eventually be justified to the most advanced possible model at a given time, that model being correctly and pragmatically described as a working absolute model.